The invention relates to a secondary assembly drive of an internal combustion engine and to a method for operating this drive. The secondary assembly drive comprises two parallel drive planes and:                a first crankshaft wheel that can be rotationally connected to a crankshaft of the internal combustion engine and is arranged in the first drive plane,        a second crankshaft wheel that can be rotationally connected to the crankshaft and is arranged coaxial to the first crankshaft wheel in the second drive plane,        an electric machine that can be operated selectively as a generator or as a motor with a machine shaft,        a first machine shaft wheel that can be rotationally connected to the machine shaft and is arranged in the first drive plane, in order to be driven by the crankshaft in the generator mode of the electric machine,        a second machine shaft wheel that can be rotationally connected to the machine shaft and is arranged coaxial to the first machine shaft wheel in the second drive plane, in order to drive the crankshaft in the motor mode of the electric machine,        an endlessly rotating first traction mechanism that wraps around the wheels arranged in the first drive plane,        an endlessly rotating second traction mechanism that wraps around the wheels arranged in the second drive plane,        a first coupling that is arranged in the first drive plane and allows the machine shaft to be taken over relative to the crankshaft,        and a second coupling that is arranged in the second drive plane and allows the crankshaft to be taken over relative to the machine shaft.        
A dual belt drive according to the class for driving ancillary drives of an internal combustion engine emerges from US 2006/0145643 A1. The individual drives in the two drive planes, called ancillary drive and starter drive below, are configured with different transmission ratios from the crankshaft to the machine shaft so that, when the belts of the internal combustion engine start up, the highest possible starting torque is transferred from the electric machine to the crankshaft. Here, both couplings, of which the first coupling allows the machine shaft to be taken over relative to the crankshaft and, in contrast, the second allows the crankshaft to be taken over relative to the machine shaft, are formed as clamping roller freewheels and are arranged in the drive sense between the machine shaft and the two machine shaft wheels, i.e., on the side of the electric machine.